Insert conversion to string in string.replace.
(missing since r13761)

R=ulan@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/12316158

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13766 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Reapply optimization of DeoptimizeIf for ia32 broken in r13633.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/12340113

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13767 ce2b1a6d-e550-0410-aec6-3dcde31c8c00